General world building information is easy to come by, but I have trouble finding information about underwater environments in AD&D 2e. While I am open to non-AD&D resources, I would prefer ones that are built around the edition I will be using.
I'm looking for information specifically oriented around building adventures underwater, and that discuss the different ways dungeons and cities might be built in a much more three dimensional world. Pregen cities are okay, but I need help designing my own.
EDITED FOR CLARITY: The characters are aquatic, and the cities exist in the water. I plan to have the characters exploring an underwater world after their home city is destroyed. They will be nomadic, going on random one-shot adventures until they discover that the destruction of their home city was intentional; at that point various small clues from the random adventures should come together to point towards Big Bad Guy.
I am having trouble building up cities that take into account the fact that the inhabitants will swim most places. What effect would water currents have on farming? Would walled-in cities have doors on the ground, on the top, or at random places in the sides? Also, what would aquatic creatures use as building materials?